C. Paturaud et al., Correlation between hardness and embedded argon content of magnetron sputtered chromium films, THIN SOL FI, 347(1-2), 1999, pp. 46-55
Chromium films were produced on steel substrates by d.c. magnetron sputteri
ng in pure argon at a target power density of 2, 4, 10 or 16 W/cm applying
a negative substrate bias voltage, V-s, ranging from 4 to 1000 V. The subst
rate temperature varied from 158 to 600 degrees C. Some experiments were co
nducted at a constant temperature of 600 degrees C. The film hardness was m
easured by Vickers microindentation. Gas content in the films was analyzed
by electron probe microanalysis. The film microstructure was investigated b
y X-ray diffraction and transmission electron microscopy. At constant depos
ition rate, while increasing the substrate bias, first the film hardness re
mained constant and beyond a threshold bias value increased from 4 to 11.7
GPa. The threshold bias value increased with the target power density. The
temperature series performed at V-s = 500 V and a target power density of 4
W/cm(2) revealed that the film hardness decreased from 12 GPa to 8 GPa whe
n increasing the substrate temperature from 300 to 600 degrees C. The micro
structure of the films was found to vary with the deposition parameters. Ho
wever, over the results for all the experiments performed here, a clear rel
ationship has been established between the microhardness and the argon cont
ent of the films. Furthermore, a relationship between the argon content and
the deposition rate was established for the films produced at V-s 500 V an
d T-s = 600 degrees C. (C) 1999 Elsevier Science S.A. All rights reserved.